Files of the form date_time_AR_plasma_environ.fits contain the emission measure, emission-weighted 
temperature and density:

The first (primary) HDU is an (nx,ny) dimensional array containing the two-hour averaged emission measure. 
WCS information is provided in the headers to construct the coordinates of each pixel:
xn_i = CRVALn + CDELTn * (i - CRPIXn)

The second (first extension) HDU is an (nx,ny) dimensional array containing the two-hour averaged emission-weighted
temperature. 
WCS information is provided in the headers to construct the coordinates of each pixel:
xn_i = CRVALn + CDELTn * (i - CRPIXn)

The third (second extension) HDU is an (nx,ny) dimensional array containing the two-hour averaged density. 
WCS information is provided in the headers to construct the coordinates of each pixel:
xn_i = CRVALn + CDELTn * (i - CRPIXn)
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Example code in IDL to read in both parameters:

data=readfits(path+'2011-09-06T21:00:00_AR11283_plasma_environ.fits', header, ext=0) ; to read in emission measure

data=readfits(path+'2011-09-06T21:00:00_AR11283_plasma_environ.fits', header, ext=1) ; to read in temperature

data=readfits(path+'2011-09-06T21:00:00_AR11283_plasma_environ.fits', header, ext=2) ; to read in density

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Example header:

XTENSION        STRING    'IMAGE'
   SIMPLE          INT              1
   BITPIX          LONG               -32
   CONTENT         STRING    'Density'
   UNIT            STRING    'cm^-3'
   NAXIS           LONG                 2
   NAXIS1          LONG               930
   NAXIS2          LONG               516
   T_REC           STRING    '2011.09.06_21:00:00'
   HARPNUM         STRING    '833'
   NOAA_AR         LONG             11283
   NOAA_NUM        LONG                 1
   NOAA_ARS        STRING    '11283'
   TELESCOP        STRING    'SDO/AIA'
   CTYPE1          STRING    'HPLN-TAN'
   CTYPE2          STRING    'HPLT-TAN'
   CDELT1          DOUBLE          0.50430500
   CDELT2          DOUBLE          0.50430500
   CUNIT1          STRING    'arcsec'
   CUNIT2          STRING    'arcsec'
   CRPIX1          DOUBLE           133.61300
   CRPIX2          DOUBLE          -82.833000
   CRVAL1          DOUBLE           0.0000000                            
   CRVAL2          DOUBLE           0.0000000
   CROTA2          DOUBLE         0.082595800
   RSUN_OBS        DOUBLE           952.30700
   RSUN_REF        DOUBLE       6.9600000e+08
   XCEN            DOUBLE           167.37250
   YCEN            DOUBLE           172.13594
   PCOUNT          LONG                 0
   GCOUNT          LONG                 1
   COMMENT         STRING    Array[5]
   HISTORY         STRING    Array[5]
   
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